/**
 *    Copyright 2009-2021 the original author or authors.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */
package org.apache.ibatis.type;

import java.sql.CallableStatement;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

/**
 * 类型处理器, 实现ORM目标， 主要完成两个任务
 * <p>
 * 1. 执行sql时，设置sql的参数
 * 2. 将数据库查询结结果映射成实体类对象
 *
 * @author Clinton Begin
 */
public interface TypeHandler<T> {

    /**
     * @param ps        PreparedStatement对象
     * @param i         SQL 参数位置
     * @param parameter 参数值
     * @param jdbcType  JdbcType类型
     * @throws SQLException SQL异常
     */
    void setParameter(PreparedStatement ps, int i, T parameter, JdbcType jdbcType) throws SQLException;

    /**
     * 得到的结果。
     *
     * @param rs         查询的ResultSet
     * @param columnName 当configuration <code>useColumnLabel<code>为<code>false<code>时，列名
     * @return 结果
     * @throws SQLException SQL异常
     */
    T getResult(ResultSet rs, String columnName) throws SQLException;

    T getResult(ResultSet rs, int columnIndex) throws SQLException;

    T getResult(CallableStatement cs, int columnIndex) throws SQLException;
}
